Updated August 2, 2026. Quick answer: Social Security withholds nothing unless you ask. To ask, you file Form W-4V, and you may choose only 7%, 10%, 12% or 22%. Not a dollar amount, not a percentage of your choosing — those four. The form goes to the Social Security Administration, not the IRS.
The four options, from the form itself
“at the rate of (check one): 7% 10% 12% 22%”
Form W-4V (rev. January 2026), line 6
This is worth checking against anything else you read. The percentages have changed over the years and a great deal of published guidance still lists a superseded set. If a page offers you a percentage that is not one of these four, it is out of date.
One separate line worth knowing: Line 5, for unemployment compensation only, allows 10% and nothing else.
Choosing among four
The coarseness is the difficulty. You cannot fine-tune, so the sensible approach is to pick the option that under-covers your Social Security tax slightly and make up the difference from a source you can tune — a pension election, or withholding from an IRA distribution. Over-withholding here is an interest-free loan you cannot recall until you file.
Two anchors. If Social Security is most of your income, your effective rate on it is probably below 10% once the taxable portion is worked out, and 7% or 10% is the realistic choice. If you have a large pension or substantial RMDs alongside it, 22% is often closer than it looks — because those other streams push more of the benefit into the taxable range in the first place.
How much of the benefit is even taxable
Never more than 85%, and for many people much less. That is a separate calculation from the withholding election and it should come first — provisional income is what decides it, and it is the reason two people with identical benefits can owe very different amounts.
The other forms in the set
W-4P is for pensions and annuities. It was redesigned and no longer uses withholding allowances — it works from filing status, other income, credits and adjustments instead. If you never file one, “If you don’t give Form W-4P to your payer … the payer will withhold tax from your payments as if your filing status is single with no adjustments in Steps 2 through 4.”, which for a married retiree with a modest pension usually over-withholds and for a single retiree with several income streams usually under-withholds.
W-4R covers IRA and other non-periodic distributions, where the default is a flat 10% (IRC 3405(b)(1)) — below the marginal rate of most people taking meaningful distributions, and the quiet origin of a lot of April surprises.
Getting the total right
Each election is set separately with a different payer, and no one is adding them up for you. The safe-harbour calculator is where they get added up: one target, one gap, and three ways to close it.
Percentages read directly from IRS Form W-4V (rev. January 2026); W-4P design and default from the 2026 form; the 10% non-periodic default from IRC section 3405(b)(1). Read August 2026. General information, not tax advice.